CHEMISTRY AND ITS DEVELOPMENT 209 



towards the end of the fifteenth century i.e., a short time 

 before the commencement of the period. As to scientific 

 pharmacy, we have already stated that its beginning coin- 

 cides with that of iatrochemistry, and it is hardly necessary 

 to add that the latter enriched it with many new prepara- 

 tions, and with a knowledge of the medicinal properties of 

 substances already known. 



About the middle of the seventeenth century iatro- 

 chemistry came to a sudden decline. That this had to 

 happen sooner or later is clear, if we consider that a true 

 medical chemistry could not possibly flourish until chem- 

 istry itself was placed on a sound basis, and before anatomy 

 and physiology had attained a stage of serious development. 

 The iatrochemists had evidently misdirected their efforts, 

 and if we should in our present structure of chemistry 

 mark the parts established by them, we would find that 

 their lasting contributions were very few. The historical 

 importance of the period lies chiefly in the fact that with 

 it came a revolution against traditional errors and a 

 change in the direction of research. 



In the seventeenth century we find the Englishman, 

 Eobert Boyle (1627-91), grasping truth with an insight 

 unprecedented, and in many respects as yet unsurpassed. 

 Boyle understood that chemistry must be treated as an 

 independent science i.e., primarily without reference to 

 applications of any sort, and that only in this manner 

 could the relationships between chemical phenomena proper 

 be discovered. He maintained that chemists should con- 

 sider as an element only a substance which, in spite of 

 exhaustive actual efforts, they have not succeeded in decom- 

 posing. And even this method, though necessary and 

 sufficient for the purposes of science, he did not regard as 

 proving the elementary nature of substances beyond doubt. 

 Still, he was inclined to consider the metals as elements, 

 and, proving experimentally that the products of the dis- 

 tructive distillation of wood are compounds, he refuted 

 the opinion then generally prevalent that dry distilla- 

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